For the "derby era" (1960's through 1980's) there are two basic types of automatic transmission- 727 and 900 series. Big block engines only used the 727 while small blocks and slant six used either type. The 900 series has several versions with variations on strength of internal components, usually people call all 900 series as a "904" although in truth this designation was used for the weakest version of the 900 trans and usually only found behind slant six engines. Outward appearance of the 900 series is pretty much the same so you would have to break inside and examine bands or count clutch discs to be sure of which one you had- 904, 998, 999, etc. The design of the 727 and the 900 is basically the same as far as the valve body and actuators are concerned, the main difference is size and strength.

3 types of bellhousings: big block B & RB engines, small block v8 LA series engines, and slant six engines.

input and output shafts are bigger on a 727

starting circa 1978 the lockup torque converters began to appear. For both 727 and 900 these had a different input shaft identified by a smooth section about an inch long from the tip before the splines began. You will find that the lockup and non-lockup versions require the appropriate torque converter to mate, I advise using a paint marker to label them if you put them on a shelf because a year from now you won't remember which one it is.... don't ask me how I know

Also, cast crank engines use a weighted torque converter and forged crank engines do not. The weight is a small rectangular shaped object about an inch long bonded to the outside of the converter.

900 pans are square with a corner cut off, 727 pans look the same but they have an additional outcropping nub under the dipstick tube. When you buy a new filter it comes with both gaskets.

1965 & older trans had a cable actuator, 1966 & later had a lever actuator for shift selection. Cable shift is not impossible to use but if you don't know what you are doing I highly recommend sticking to the lever shift versions. Any aftermarket shifter sold for derby purposes is designed for lever style. 727 and 900 trans can use the same derby shifter.

For derby use, it is important to "fix" the kickdown lever as a minimum preparation item. Simplist thing to do is remove the linkage that goes to the carburetor and tie or wire the kickdon lever on the transmission back. How far back? Up for much debate. If you work it by hand, you'll feel a point where it goes from having no tension on it to have some spring tension resistance. If you consider the amount of travel from the point resistance picks up until travel stops, this is the working travel. Most people will recommend fixing it in a position that is about 3/4 of the travel.

What the kickdown is and does is a more complicated topic I'll save for a different post, but if you leave it loose you create some internal pressure conditions that can easily contribute to early transmission failure.

to adjust bands-
the basic recipe says to tighten to 72 lb-in and then back off two turns, now in various publications I've seen everything from 2 to 4 turns for the 900 series transmissions rear band although the front band always seems to be 2 turns. I do it by feel but maybe if you aren't comfortable with that you could split the difference and go with 3 turns...? I would expect that to be close enough.

for rebuilds-

[= x-small]you'll probably need a slide hammer to get the pump out. You'll need a quality set of snap ring pliers, you can do it with cheapies but it can be frustrating. To get the clutch pistons apart and change the seals you'll need a special tool and/or a shop press, you can buy one or make your own tool or just skip this step. I frequently opt to skip this step out of laziness the main thing is to replace the clutches and bands[/]

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So will a 727 transmission bolt to any small block mopar? 273 318?

727 will bolt to a 318 thats what I run works great.

not all 727s have same bolt pattern. small block 727 bolts to small block and big block is for big block. they don't interchange.

referencing what I wrote in the first paragraph: the 727 was available for the big block, small block, and /6

referencing what I wrote in the second paragraph: there are three different bellhousings: big block, small block, and /6

so not all 727's are the same.... if you have an LA series small block (273 or 318) then you will need a 727 with the right bellhousing. A 727 for a big block or a /6 will not fit.

ok thanks reason i asked is because im buying a 273 thats supposed to have a 727 with it.... just wanted to know if that was possible...

X2! Until it gets hot...

would a yoke off a small block 727 fit a big block 727?

bolt on yolk for like a slider? if so yes

only real difference between BB and SB 727's is the bellhousing, pretty much everything from the pump back is the same.

yup thats what i needed to know thanks

That will save me $100

How would I go about bolting an AMC th400 from a 79 wagoneer up to a 318 from an 86 ramcharger? Is there a conversion plate / adapter for this?